Citrus fruits have long been recognized as valuable sources of important nutrients. More recently, health benefits and disease retarding or treating benefits of citrus sources have come to be more fully recognized as advantageous and beneficial when ingested. Accordingly, there is a general belief that increasing the intake of citrus-originating foods is a beneficial and important objective in the overall scheme of human health.
Segments of the population are less than enthusiastic about certain characteristics of citrus products, such as bitterness, acidity, off flavor notes, browning, and a thick consistency. Concerns about these types of characteristics are perhaps most prevalent when the citrus product or ingredient is grapefruit originating. Other citrus fruits can present these types of concerns, including orange, tangerine and lemon fruits. In terms of volume of juice and percentage of dislike in the juice-consuming population, grapefruit products, non-traditional orange-originating products, and some traditional citrus products, present both the greatest challenge and the most promising potential. Heretofore, these resources have been underutilized due to these types of characteristics, which characteristics can be considered objectionable to certain segments of the population, or can otherwise detract from juice quality.
Numerous approaches have been taken in the past which incorporate various filtration and ion exchange technology in order to operate upon citrus juice sources with a view toward preparing a variety of different products and byproducts. These approaches typically do not substantially change the characteristics of or operate on pulp components. It has long been known that citrus pulp can be separated from citrus juice. Often, this involves removing pulp so as to provide a so-called clarified juice or serum, which can be subjected to debittering. In those instances, the separated pulp is discarded, used in low-value products such as animal feed, or is stored for reintroduction of some of it into juice products which are formulated to have high pulp contents.
Removal of components from citrus with resin is generally known. Mitchell et al. U.S. Pat. No. 4,514,427 notes that bitter narigin and limonin can be removed from citrus juices by contacting the juice with a weak base anionic exchange resin having a matrix of a styrene polymer and functional groups derived from a monoamine or a polyamine. Puri U.S. Pat. No. 4,439,458 describes reducing flavonoid and/or limonoid induced bitterness in citrus fruit juices through adsorption of such bitterness componets by a resin. This patent notes that naringin is a typical flavonoid, that limonin is a typical limonoid, and that the resin can be a styrene divinylbenzene cross-linked co-polymer. Norman et al. U.S. Pat. No. 4,965,083 has a general teaching along these lines, and this patent discloses a post-crosslinked adsorbent resin.
Divinylbenzene adsorptive resins are disclosed in Meitzner et al. U.S. Pat. No. 4,297,220, in Ifuku et al. U.S. Pat. No. 5,734,046, and in Takayanagi et al. U.S. Pat. No. 5,885,638. Mozaffar et al. U.S. Pat. No. 5,817,354 specifically teaches the use of Rohm and Haas AMBERLITE® XAD-16 styrene divinylbenzene resin to adsorb, and thus remove from citrus juices, bitterness compounds such as limonoids, including limonin, nomilin and other compounds, and flavonoids such as narigin and hesperidin. In general, the art recognizes that adsorptive resins such as AMBERLITE® XAD-16 of Rohm and Haas are useful for removing flavonoids and limonoids from citrus juice sources.
The subject matter of each patent or publication mentioned herein is incorporated by reference hereinto. For example, the chemical structure of the styrene divinylbenzene resins is disclosed in the thus incorporated patented or published subject matter.
As noted generally herein, in many instances, citrus fruit is not used in a high value manner or citrus materials are not particularly palatable or suitable for commercially distributed products. For this reason and others, citrus fruits are not used to their full potential, and many valuable nutrients are not put to use in a manner which directly benefits people. This is particularly true for separated components which include citrus bitterants at naturally high levels. There is accordingly a need for approaches which allow a more complete realization of the potential of citrus fruits, and especially of citrus juices, grapefruit sources, and currently under utilized citrus sources in general which have components that create concerns regarding bitter flavor or sensory notes or regarding off-favors which develop over time or otherwise are present in the citrus source.
Fruit juices of interest include those for use in juice sources which are concentrated and which can be reconstituted before distribution to the consumer or thereafter. These so-called “from concentrate” juices undergo an evaporation or concentration procedure. The invention also is of value for processing fruit including citrus fruit into juices which are consumed without ever being concentrated or subjected to an evaporation process. The invention allows juice sources—ranging from relatively low quality peel juice to Grade A juice sources—to be improved by removal of less desirable components.
The juice products which can be improved according to the invention include filler juices as well as stand-alone juices. Many blended juice products are currently marketed. Most such products include as a primary component what has come to be known as “filler” juice. A filler juice is a relatively inexpensive juice source which is suitable for blending with other juices or juice flavors which are generally known as “key” flavors. These key flavor juices or flavorings are generally dominant to the senses, especially taste, with the result that a blended juice product can contain relatively low levels of key juice or flavor sources while still achieving the desired blended flavor of key juice(s). Primary filler juices have been apple juice and/or grape juice, particularly white grape juice. These traditional types of filler juices are generally considerably lower in nutritional content than are citrus juices. The use of citrus sources as filler juices has developed by technology such as in U.S. Pat. No. 6,054,168. Filler juices should be relatively low in cost and have a relatively bland flavor.
Accordingly, there is a need for juice sources, whether they be stand-alone juices, juices for blending or filler juices, which can themselves be improved by removing naturally present components which have negative effects on juice products as processed and/or after packaging and storage.